The present invention relates to an ultrasonic diagnostic apparatus for transmitting an ultrasonic wave to a subject to be examined, receiving an echo from the subject and creating an ultrasonic image on the basis of that echo signal.
In recent years, a B mode for representing a tissue structure in a subject's cross-section and a mode different from a color Dopper mode for representing, in color, a blood stream state in the subject cross-section have been developed in the field of the ultrasonic diagnosis. A tissue Dopper imaging mode allows the extraction of only a lower Dopper frequency and the imaging of a slow motion alone of the cardiac muscle for instance. And the color kinesis mode provides an easy-to-acquire tissue motion by extracting an endocardial boundary and overlaying those boundaries at different o'clock time phases in different colors.
The 3-dimensional mode image enables a 3-D image to be constructed from a plurality of images obtained from the multi-slices of the subject.
Of these, the 3D mode is of high clinical significance and has recently received attention. The 3D mode involves a vast amount of data and presents the problems with an increase in circuit size, a rise in cost and a slight loss in real time.
Some recent ultrasonic diagnostics apparatus achieve a frame rate (high time resolution) of as high as 50 frames/second. On the other hand, the dynamic capability of the human eyes is restricted to 10 to 15 frames per second. For this reason, the observer simply acquires a portion of rich information the above-mentioned high time resolution provides.